Double-Glazed Windows vs. Storm Windows Double-Glazed Windows vs. Storm Windows

One of the most attractive advantages of being a home owner is that, as we live, love and play each day, our home’s value appreciates. “Appreciation” is the best reason for buying a home and staying put – it’s money in the bank each year.

Home improvements add even more to our home’s value, as well as increasing our comfort level and our over-all feeling of satisfaction and pride in our home.

Among all home improvements, replacing or updating windows brings major rewards: utility bills drop, Dad’s recliner by the big picture window is actually a cozy and warm spot, and when you do sell your home, nothing impresses a buyer more than the lure of good windows.

The city of Boulder, Colorado, in a January 2006 update, cites several window efficiency studies and reports, among them, a 2004 study in Denver. Published by the Southwest Energy Efficiency Project for the U.S. Department of Energy’s “Building American Program,” windows in Denver were oriented differently in winter and summer to utilize the best energy advantage possible. The study shows that “double-paned windows lose ten (10) times less heat in winter than single-pane, and have 40% less summer cooling loss.”

Also cited is an article from Home Energy magazine by Colleen Turrell, titled “Storm Windows Save Energy” (July 2000). A pertinent point in the article is that “storm windows make the biggest difference on the lowest quality windows and at higher wind speeds.” This is no small revelation. If you have poor and failing windows, combined with a small budget, you can still experience good results by investing in storm windows. When we get serious about improving our home’s energy efficiency, double-glazed windows and storm windows are the two most considered options.

What are double-glazed windows?

Double-glazed windows consist of two panes of glass separated by a layer of air, or inert gas, and then sealed. The glass and the air act as insulators. In addition to two layers of glass, and the sealed air pocket, the exterior layer of glass, the one that faces the interior of the room, has a specially coated surface. This coated surface reradiates or reflects heat in cold months, as well as reducing some heat gain during hot weather.

Why are some double-glazed windows better than others?

Double-glazed windows with an inert gas between them (usually Argon) are considered a better insulator than just the sealed pocket of air. Gases have a higher density level than air, allowing less heat to escape, or less cold to enter.

The choice of glazing film makes a compelling difference. No matter your climate, new technologies of low emissivity (low-e) films can further reduce energy losses by about 25 to 50 percent. The interior of your home can benefit from a reduction of fabric-fading UV rays, as well as reduced condensation resulting from warmer interior window surfaces.

What are storm windows?


A storm window is a separate window that is removed and stored at the end of the season. The storm window is purchased either as an outside window attaching to the exterior existing window frame, or as an interior storm window, installed from the inside of the house. Storm windows are generally made of glass, plastic, or plastic sheets. Plastic options are Plexiglas, acrylic or polyethylene, all of which are generally less expensive than glass. While glass offers more clarity, it is also more fragile. Plastics are lighter but less durable than glass and are susceptible to scratching and yellowing.

When are storm windows a good option?

Storm windows are feasible when cost is the determining factor. According to the U. S. Department of Energy, storm windows are not a good insulating factor, but they do significantly reduce air leakage.

Which is best: Interior or Exterior Storm Windows?

Interior storm windows are easily cleaned and removed from the comfort of inside your home. Exterior storm windows must be very sturdy, and able to resist the elements of your climate. Interior storm windows have no outdoor exposure so there is less maintenance and less need for durability.

The interior storm window works by preventing the air, in your already cozy room, from exiting out the window. The exterior storm window prevents the outside air from penetrating the exterior window and entering your cozy room.

Interior storm windows usually utilize weatherstripping to create a superior seal. Exterior storm windows cannot use weatherstripping as it absorbs and traps moisture from the outside elements. Exteriors use a tiny “weep hole” to allow moisture to escape, which may slightly compromise the efficiency of the exterior storm window.

Both double-glazed and storm windows will add a measure of security to your home environment. Each additional layer of glass or plastic is a disruption for an intruder. Add home security to the increased “coziness” factor” and the importance of reduced energy bills, and the need to update single-paned windows becomes clear.

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